The Advantages of Experimenting
by SteelyThePally
Summary: Hanji decides to experiment on her two favorite Titan Shifters, Eren and Annie, for three straight days. Little does Eren know that he's not only coming back from it to his normal routine with a tired body, but with something else as well. [Lame summary, Eren X Annie, mild AU, rated teen for possible violence and language]


_**Here's my first fanfic related to Shingeki No Kyojin. I've recently finished the last episode (No manga, sadly. It's hard to find it around where I live ;~;), and, after searching around on the internet, I ended up loving the EreAnnie (Eren X Annie) shipping pair. Something snapped in my mind to make a story centered around the lovely pair relating through their Titan forms. If I screwed up the characters, don't feel afraid to talk about it on your (much appreciated) review.**_

_**Oh, please: Do review. I would like to receive feedback (Good or bad) on this... thing.**_

_**Disclaimer: I don't own Shingeki no Kyojin or any of its characters.**_

_**...**_

_**12:04 AM, Erwin Smith's Office**_

"Hanji, are you sure of this experiment of yours?" Erwin's voice calmly asked, eyes set on the Titan-loving woman sitting just behind his desk.

"Yes!" Hanji exclaimed loudly, abruptly shooting her arms up. "It's completely safe! Eren is in kind-of-total control of his Titan powers, and Annie herself is even more experienced than him! Nothing will go wrong for those three days, I assure you."

Erwin gave a low sigh, resting his elbows on the wooden surface of his desk. He knew how reckless Hanji was with her obsession for Titans, but putting two Shifters who had exchanged more blows than words in the past next to each other while running experiments on both was on another level of insanity. Not to mention the savage, irate behavior demonstrated by Eren during his battle with Annie at the innards of Wall Sina. The commander closed his eyes for a second, as if allowing Hanji to go on with her explanation.

"We won't stay very far away, but far enough to not cause any trouble with the other members, or damage the castle, sir." Hanji went on, closing her eyes and smiling widely at the serious commander of the Survey Corps.

Erwin didn't flinch a single muscle, his mind racing to decide whether should he allow Hanji to execute such plan. He knew very well that Annie wasn't any kind of amateur in the subject of controlling her Titan. The commander doubted of Eren's ability with his Titan for a split second, considering his short-fused attitude. It was quickly acknowledged to him that Eren gained more control over his Titan as Hanji injected various substances, let alone his quick transformations. Taking in a deeper breath, Erwin looked at Hanji with a simple smile, a backup plan set on his mind.

"...As you wish, Hanji. Please, do take care. And don't hesitate to do what's right." Erwin finally spoke up, his head lowering but his features were still stamped with his stoic expression upon raising his head again, no traces of his faint smile. Hanji nods frantically. She gives a brief salute before standing up in the blink of an eye, her feet racing and bringing her out of Erwin's office.

Outside, Hanji spun on her heels until she came face-to-face a short, blond figure. He was dressed in the Corps' signature green cape, hiding most of his body. His eyes gazed up in a split second as he noticed the return of his superior.

"So, sir… how did it go?" Armin asked a tad reluctantly.

"Armin, my dear! Grab your 3DMG and let's look for Eren and Annie!" She bubbly replied to his question, hopping in place before excitedly walking down the hallway. "Oh… and some sleeping bags, too."

...

There he was, again. That idiot, so eager to die. So eager and convicted to try and defeat her. Behind her raised fists, she gave her usual icy stare deep into his flaming emerald orbs. Even with such a gaze directed to him, Eren Jaeger didn't seem to lose the fire burning inside him. His face was marked with multiple bruises, his hair was drenched in sweat. Yet, his eyes still retained that burning passion of his. _How can this idiot still beg for more after so many damn tries?_

Eren smirked mockingly when an idea to finally beat Annie in a spar came to mind. He faked trying to deliver a fierce left hook, already seeing Annie raising her right arm to try and block his attack. Quickly cancelling his blow by incredibly slowing his speed, Eren clenched his right hand into a tight fist and punched his opponent's stomach with all of his strength. Annie let out a breathful of air and her eyes went wide as dinner plates, leaning her upper body forward.

He saw that she was briefly stunned and, in the blink of an eye, Eren used his right leg to kick her shins with brutal velocity and strength. The world around him slowed down upon seeing Annie finally falling head-first on the ground. To finish his attack, Eren raised his right arm in the air before slamming his elbow against the back of her head, sending her even faster to the dirt surface.

Annie barely shot her arms forward to stop her fall. She landed on the ground with a shy ***thump***, followed by a rare grunt of pain coming from her. Eren quickly wrapped an arm around her neck and raised her body next to his chest, immobilizing her limp arms with his free limb. Finally, he pressed his knee against her spine. Held in a incredible triangle choke, Annie gasped for oxygen in order to show her defeat. One could see Eren's emeralds flash with joy as he released her instantly from his grip and victoriously stretched his arms. "I finally won! Yes! Yes!"

"Eren, why are you so rough with such a weak, fragile and frail maiden like me?" Annie asked in her cold tone, though one could notice a hint of amusement in her voice.

Eren chuckled to himself when he turned his head towards Annie, who already sat up and dusted herself off. He opened his mouth to respond, but…

"Good morning, my little Titan Shifters~!" A sweet voice came in and interrupted their actions. They looked up to face the speaker, their eyes widening slightly upon seeing Hanji Zoë happily grinning at them, Armin's short frame right next to her. They noticed that she was equipped with her 3DMG, as well as Armin.

They wasted no time and stood up, tapping their clothes briefly before gazing at the Lieutenant.

"Good morning, Lieutenant!" Both Eren and Annie greeted in unison, much to Hanji's surprise.

"You sweeties don't need to act so formally when around me, c'mon!" Hanji replied with a short giggle.

Considering all the gentle names Hanji was calling them, Eren raised an eyebrow in suspicion: Her eyes were sparkling with curiosity, not to mention that they darted from Eren to Annie, as if in utter indecision on who to stare at. Eren sighed lowly when he came to the conclusion that she wanted to experiment with them. He glanced to his side to see Annie, still wearing her usual expression lacking emotions, with an air of obliviousness surrounding her.

Before Eren and Annie could even try to greet Armin, Hanji moved like lightning to their backs, her arms flying around their necks and pulling their heads together into a painful collision. Both Shifters groaned in pain, but Hanji simply started brushing their heads against one another, a faint blush spread on her face.

"My babies!" She says, in a tone that even Eren felt his heart jump. "We're bound to have three wonderful days!"

Hanji removed her arms from their necks and walked slowly towards the great grasslands surrounding the Survey Corps' HQ. The two Shifters rubbed their heads in pain, groaning and obviously cursing under their breaths. Armin walked over to the duo and smiled warmly.

"Hello, Eren, Annie."

"Yo, Armin!" Eren greeted his friend with the same warmth.

"Armin." Annie said solely, rubbing the side of her head that collided with Eren's, then completing her action by placing a lock of her golden hair behind her ear..

"We need to follow Hanji, c'mon." Armin rapidly added as he rearranged the large bag on his back and started following Hanji in her tracks.

Eren and Annie didn't hesitate to go after him as well, walking in a steady pace through the grass. Eren neared his friend and nudged him, in hopes of getting his attention.

"Armin… why are you carrying this big-ass bag?" He pointed his index finger towards the dark green rucksack resting on Armin's back. The color matched perfectly with the Scouting Legion cape that he was wearing.

"Ummm… it's for an experiment that Hanji wants to run on both of you." Armin's words managed to catch Annie's attention, considering on how she turned her head to pay attention to their conversation. "Something snapped in her brain and she now wants to spend three straight days while running inumerous tests on your Titan forms."

"Wait, what? You ain't serious, are you Armin?" Eren asked, a hint of angst in his words.

"I am serious, Eren. You know how that woman is crazy about Titans. She even asked for Erwin's approval on the fact."

Eren's mouth fell agape at those words. He knew that Hanji was eyeing him and Annie constantly since the day that the latter emerged from her crystal prison, obviously due to the fact that she now had two Titan Shifters in the Survey Corps. Knowing her, they both knew that she wouldn't waste such an opportunity.

Minutes passed on as they walked in their group of four, nothing being heard aside from the gentle whispers of the wind on their ears. Not to mention Eren's bombardment on Armin for answers on whatever happened to Hanji to come up with such an idea. Annie hugged her chest while taking a small distance from Eren and Armin, who kept sharing looks with each other but said nothing. Even with her light blue gaze set forward, she could feel Eren throwing sideway glances at her with each minute that passed on. What those looks carried she couldn't tell, but she felt that they were constant.

After a few more mere minutes of complete silence, Eren ended up bumping into Hanji's back the second she skidded to a complete halt. He rubbed his forehead momentarily before backing away from the woman. The three teens all kept their attentions focused on the researcher when she spun on her heels and looked with excited eyes at the trio.

"It's here! You can set your bag down, Armin."

Armin gave a breath of relief, dropping the heavy rucksack on the grass beneath his feet. Hanji moved next to the bag, sticking a hand inside and then bringing them back out with a notebook and a pencil in her grasp. If one looked closely, they could see that she was shivering in joy, alongside the rather stupid grin on her face. Eren's stare at her became a bit worried.

"So, Shitty Glasses, what the hell are you doing here?" A familiar, cold voice came from behind. Everyone looked towards the source and saw no one other than Corporal Levi. He was wrapped around his cape, geared in his 3DMG, and strangely wielding his swords openly.

"Oh, good morning, Levi!" Hanji greeted him with a large smile accompanied by the bubbly tone of voice, totally shrugging off his harsh words. "What brings you here?"

"Erwin sent me to… supervise this little experiment of yours." Levi replied without much interest. He moved his eyes through Eren, Annie and stopped them at Armin. "I see that you brought the little brat, the icy bitch and of course Mr. Brain. Impressive selection."

Annie barely changed her expression at the way the Corporal named the young members of the Legion, but she elbowed Eren to get his attention.

"Does he even try to call his subordinates by their names?" She asked, showing a bit of curiosity in her typical stoic tone.

"You'll get used to it in a while." Eren replied, not even turning his head to face her as he focused his green orbs in Hanji.

Levi clicked his tongue in boredom upon seeing Hanji nod frenetically at him in approval. He shook his head before walking away from the group, resting on top of a small hill with his eyes constantly watching the scene below. Hanji shrugged it off and now looked at the two young Shifters, trembling in joy. "Okay, I think we can start. Armin, you take notes on what I tell you, okay?"

The nod coming from the blond boy was enough to make Hanji's heartbeats skyrocket. Armin had become her number one assistant in her experiments whenever Moblit wasn't available, what proved to happen very often recently. She abruptly threw the notebook and pencil on his hands, forcing him to desperately try to get a good hold of them. Upon grasping with safety on the objects, Armin opened the notebook on a random page and held the pen close to the sheet, ready to put down any notes that Hanji would shout at him.

"Okay, okay, let's start this already!" Hanji exclaimed gleefully, moving closer to Eren and Annie. She pushed the teens aside in a way that they were in the opposite directions of each other. "Look, firstly, I need you two to transform into Titans!"

Eren raised his eyebrows at her request. He knew very well that he couldn't transform without a clear goal in his mind. His usual objectives were to slaughter Titans, but this time could prove otherwise if he managed to shift into his Titan form without a major goal. After all, he didn't want to disappoint Hanji, neither did he want to stay in his human body while Annie humiliatingly towered over him. Who knows what she would do…

Focusing his mind solely in the objective of turning into the 15m beast, Eren nodded to Hanji and closed his eyes, internally shouting to himself his goal. With his eyes still closed, Eren raised his hand towards his mouth. Much to his bad luck, Eren didn't perform the familiar act of biting down on his hand, his irises shrinking to a pair of minuscule green orbs as the gigantic frame of the Female Titan emerged from a cloud of scorching steam. His hand dropped from his mouth and Eren simply stared at the Titan before his eyes.

Annie's eyes widened slightly as she didn't see Eren's Titan form next to her. She lowered her head and stared down at the tiny, now fragile frame of no one other than Eren Jaeger glancing up to meet her large, blue orbs. Without a word being said, she crouched slowly towards the boy, her eyes never leaving him. She moved an arm next to him, close enough so that her hands opened precisely around him. The boy gasped loudly upon feeling a tight pressure around his whole body, only his head protruding out of her closed fist.

Eren gasped loudly upon feeling his feet leaving the soft grass beneath him. It was obvious that he was being lifted off the ground at this point. With his arms inside Annie's tightly closed hand, Eren couldn't even try to beat his fists against her hand to stop the climb. Realization struck him when he remembered not having his 3DMG on when coming to this area, mainly due to his earlier spar with Annie. Cold sweat ran down his face as he desperately tried to move his body, achieving no success. He swallowed the lump in his throat and closed his eyes, hoping for any intervention coming from Hanji, Levi or even Armin.

Well, said expected group was watching the scene in utter confusion from ground level. Hanji scratched her hair, trying to make sense out of the situation. Armin himself stared at the two with examining eyes: The expression splayed on the Female Titan's face demonstrated uncharacteristic warmth and tenderness if one took into account who was inside the Titan. The short boy found the task of moving his body pretty difficult, unabling him from alerting Hanji from possible dangers.

Eren suddenly opened his eyes as he felt his body go from his original upright balance and fall into a hard yet warm surface. Using his elbows to raise his upper body, Eren groaned quietly and opened his eyes. He was met with a pair of large cobalt irises gazing deep into him. His heart skipped a beat as he noticed that her fleshy lips were actually curled, even though softly, into a sweet smile. The boy felt his face heat up upon noticing that he was laying on top of her outstretched palm.

Moving her free hand up to where her 'toy' was, Annie brushed her index finger along his back. This made Eren gasp and sit up, his spine unusually straight. A deep, vaguely feminine giggle could be heard coming from her mouth. Her eyes closed ever so slightly, giving Eren enough hints that she was amused with his reaction. The finger reached for his scalp, brushing his dark brown hair in slow circles. It felt frighteningly… good for Eren, who couldn't move due to the racing thoughts in his mind.

Suddenly, the familiar sound of a wire being fired rang in his ears. The Female Titan didn't even flinch when a hook stabbed her shoulder, being buried in the hard skin with ease. Followed by a short burst of gas, the distinct hissing of a 3DMG echoed in the midday air. In a matter of seconds, Levi emerged from below and landed gracefully on the shoulder of the 14m Titan. His blades were unsheathed and ready to strike.

"Oi, Leonhart!" He exclaimed in an authoritarian tone. He knew that he caught her attention when he captured her left eye staring at him with expressionless eyes. "Put Jaeger down. That's an order.

Grunting towards Levi's request, much to Hanji's surprise, the Female Titan brushed her bony finger against her 'captive' for one last time before kneeling down to ground level.

…

_**1:25 PM, Outskirts of the Survey Corps' HQ**_

"So tell me, Arlert: How comes that you carry a chessboard along with all the pieces inside your rucksack?" Levi questioned, barely looking up at Armin as his eyes were fixated on the mentioned object protruding from the green grass. He passed a hand on his forehead, removing the bead of sweat that formed on his skin. It was surely a hot day.

"Um, well, Hanji actually chose me to help her with her experiments alongside Moblit. As her experiments went on, they began to get more and more boring. So boring that Moblit didn't even have to be warning Hanji of the dangers of experimenting with Eren. One day, he came up to me and showed this board. It has been inside the rucksack since then." Armin explained, wearing a joyful expression in his features. He stretched his arm to move one of his pieces, placing it down with care on the selected square.

"Oh. Now I know where the hell you were when I was searching for you during your cleaning duties." Levi doesn't change his tone on the slightest, bringing a hand to his chin and scratching it in thought.

"I-I'm sorry sir! I didn't want to slac-"

"Oi, Mr. Brain. I'm actually relieved by the fact that you found something to busy yourself with when Four-Eyes is doing whatever she does to Jaeger." The Corporal quickly interrupted Armin's apology.

Armin took in a deep breath and waited for Levi to make his turn. The wait proved to be quite long considering how fast the short man moved his pieces whenever Armin ended with his turn. Passing a hand on his face to take his golden strands out of his line of sight, the boy noticed that Levi wasn't looking at their game anymore: His sight was set somewhere else. "It seems that Leonhart isn't having a good time with Shitty Glasses."

Turning his head to his right, Armin found the scene before him pretty… confusing. Eren was sitting on the grassy surface, eyes closed and his hand painted with a smear of blood. Opposite to his best friend, was Hanji and Annie. Strangely, the Titan was sitting with her legs half-stretched in front of her. The woman next to her held one of her swords, thrusting it back and forth into Annie's leg. Much to Armin's surprise, Hanji was actually using her swords to loosen the fibers and grabbed them as if they were wires. Annie visibly winced every time she felt the blade either snap or render her muscles useless.

Of course that the boy noticed Eren's resting figure. The blood on his hand told him everything: His mind was clouded by something. It seemed obvious to jump to the conclusion that he was a tad shaken by the strange show of affection that Annie gave him. _There's something more in that… Annie acted way too… sweetly? If Titan Shifters need a clear objective in their minds to transform, then what was Annie's? What happened to Eren since he didn't transform?_

Out of the sweet silence that they were enjoying, a loud, glass-shattering crack assaulted both Levi's and Armin's unsuspecting ears, forcing both men to close their eyes shut in instinct. The blond shot his hands up and briefly held them at the sides of his face, hoping to make the infernal ringing cease. Finally opening his eyes, Armin noticed that he and Levi weren't bathed in sunlight anymore. A glance to the side, and they saw Eren's massive frame standing proudly in the afternoon air. His head completely eclipsed their spot from the sun's golden rays..

"Yaaaaaahooo!" Hanji crazily shouted, dropping her sharp blades beneath her feet. She darted, even though in a trembling fashion, toward Eren's foot. A surprised growl escaped his lipless jaw when he felt two tiny arms try to desperately grasp around his ankle. One glance downwards and he saw the Lieutenant screaming happily.

"Well, Arlert." Levi said, raising from his sitting position and gazing off of the chessboard. "We'll have plenty of time to play later. Now, just do whatever Four-Eyes orders you to." And then he trailed off to a steeper hill to watch over the scene.

The boy gave in a deep breath before bending down to grab the notebook and the pencil laying next to the chessboard. Slowly moving to where Hanji was insanely yelling at nothing in particular, Armin sat down at a considerable safe distance from the Titan-loving woman and her… babies.

…

_**6:05 PM, Near the forest east of the Survey Corps HQ**_

"Hanji." Levi said as he sniffed the woman next to him, his face contorting with disgust the moment he pulled back. "You're stinking."

"I am?" Hanji asked, mocking him with her obliviousness. She raised an arm to the air and sniffed her armpits. "Ah, it's not so bad, c'mon!"

"You're smelling like Eren's breath at morning." Levi commented, taking one step away from Hanji.

"Oh! Maybe it's because that I was checking inside his jaw earlier today!" She replied way too calmly for someone who had been inside a Titan's mouth.

"You…"

"Not to mention that I was inside Annie's too! They both have got beautiful teeth!"

The Corporal's eyes widened, something rare to see coming from such an emotionless person. He literally teleported to Hanji's back and started pushing her down the dirt path, leading to the innards of the nearby forest. The task was proven to be quite difficult, considering how tall Hanji was near him. He momentarily left her standing at the very entrance to the forest, ran back to where the rucksack was, stuck his hand inside and brought out a sponge alongside a piece of soap. He knew that there was a river not far away from where they were, and he knew that he wouldn't leave a hint of stink in her clothes- or not a hint of stink in _Hanji_.

Armin barely noticed their talk, his eyes fixated on the two Titans before his eyes. Eren leaned against a particularly large tree, his legs crossed and his ever-burning emeralds reflecting the sunlight that died in the horizon. Annie was right by his side, her legs stretched in front of her and her pale sapphire irises showing signs of exhaustion. The boy himself was nearly collapsing on his head while still holding the pair of objects in his hands. Pages were now filled with tons of useful information, many being Armin's modified paragraphs on the results they had got from the tiresome evening.

Eren fixated his gaze in the setting sun. He was equally exhausted if compared to Annie. And maybe a tad disturbed, too. He was stabbed in the chest, he had his eyelids severed when Hanji noticed his third, transparent one, he had his limbs torn off and his bones broken by no one other than the Female Titan to test how fast he could regenerate. As well attempt to learn from Annie on how to concentrate in one particular wound. Well, he was a bit thankful for the fact that he got some revenge when they switched roles.

The sun finally slipped into the line of the horizon, the great green plains now being shrouded in a comforting darkness. Silence reigned between the two Titans and the blonde teen sitting next to them. They both spotted Armin shuffling inside his rucksack for a second before bringing out a dark olive green sleeping bag. He set it down on the ground and spread it to its full length, slipping a hand inside to open some space for his body.

The Titan watched him in mild confusion, but his mind snapped when he saw Armin's utterly worn face. It even reminded Eren of their times as children, when they would spend countless hours running around the streets and alleyways of Shinganshina. While all of those who had seen the Rogue Titan's face only saw hideous expressions of pure rage and ire, they never expected to see a toothy smile forming on his features, despite his lack of lips. His green eyes flooded with nostalgic happiness.

Now seeing that Armin took out some rations from the rucksack, Eren let a low grunt. His vision seemed to be closing in, being reduced as the second passed by. A strange feeling scoured his body. What sounded like flesh opening came to his ears, alongside the eerie sensation of having his body being pulled off from his Titan body. The boy gasped upon seeing the messy back of his Titan's hair, its head lowered slightly. He tried to move his arms, only to see that they were connected to long strands of his flesh. This hard fiber was also connecting his legs, arms, even his cheeks to the Titan.

"Eren." An icy voice came to his earshot.

"A-Annie?" He stuttered, trying his best to turn his head towards the sound of the voice. He groaned upon the resistance that the flesh nearly enveloping his whole body gave him.

"Give up on trying to move out of that." The voice responded. The quite blunt tone was enough to Eren have a good idea of who he was talking with.

"Wait, Annie. Where am I?" Eren questioned.

"You're outside your Titan, Eren. When the sun sets, instead of just being disabled, Titan Shifters stick out of their Titans and stay in the same state that you are right now." She was quick to respond. "Only more experienced 'pilots' can get out of those goddamned webs…"

"So, this means that I'm staying like this until the sun rises?"

"Yes. Get some sleep, you're not accustomed to stay so many time inside your Titan." Annie suggested, giving a tired yawn to try and reinforce her point.

Eren gave a shortened nod. It didn't felt good to be stuck in this pose, but neither did it feel bad. He did feel his body getting sore by the minute, not to mention that his eyes were threatening to close. His brain slowly replayed the moments that he had passed through his day, such as his early talk with Connie and Jean, having his breakfast with Armin and Mikasa, running to the courtyard to meet up with Annie…

...And of course the moment when he failed to transform because of his watchful eyes looking at the Female Titan. The memories of being grabbed by her enormous hand, struggling in her grasp, uselessly trying to break free, being dropped on her palm and having his hair brushed by her finger. His eyebrows shot up when he tried his best to face Annie, opening his mouth to speak:

"Annie… about when you grabbed me earlier today…"

"Yes?" Her reply came a tad more… nervous? Eren couldn't tell exactly.

"Why did you do that in first place? You looked pretty-"

"Isn't it obvious, Eren?" Annie rapidly cut him off, her tone coming a tad more happily, almost uncharacteristically to her usual bored timbre. It echoed in his ears, clear that she tried to imply something else in her sentence.

Eren took a moment to hum in thought. He frowned his eyebrows, deciding that he couldn't make any sense out of her question, he soon said:

"...No, I guess?"

Annie's eyes shot wide for a split second, and then she let out a mildly annoyed groan. Deep within her, as much as she hated to have this feeling, she simply adored his obliviousness. Even if it rendered her plans useless. At the moment, Annie couldn't care at how adorable he sounded when he was so absent-minded upon being confronted about her earlier action. Now she simply lowered her head in defeat and sighed. "Just… rest. You'll need it."

She could hear Eren give a baffled groan. She clenched her fists to try and minimize her discontentment. Finally shaking her head, Annie closed her eyes and decided to finally get some sleep. However, one though insisted in floating around inside her mind.

...She should have stuck with her plan: Wait for Eren to train with his 3DMG in the woods on his own, transform in a Titan, snatch him, lead him somewhere quiet, pet him relentlessly and see how long it would take to make him snap and see what she _really _wanted from him.


End file.
